ENZYMES DORMANT IN THE INTACT SPORE 117 



pacity which was seen in intact spores following proper activation. The in- 

 active enzyme system was that whose activity was only recognized in dis- 

 rupted spore preparations. This condition was found in freshly harvested 

 spores and in aged, heat-activated spores which had undergone prolonged 

 storage. 



The mechanism of glucose oxidation by spores of B. cereus var. termin- 

 alls largely followed a non-phosphorylated shunt pathway, being initiated 

 by a DPN- linked glucose dehydrogenase. A deficiency in TPN or some 

 other part in the electron transport system, either through metabolic loss or 

 poisoning, would readily produce the inactive respiratory state observed. 

 Synthesis of these cofactors or a destruction of an inhibitor during aging 

 of the freshly harvested spores would elevate the glucose oxidizing capac- 

 ity of the intact spore. 



The conversion of the dormant enzyme system to an active system pre- 

 sents a different problem. In the case of glucose oxidation, activation was 

 achieved by either prolonged heat treatment or by adenosine under condi- 

 tions precluding germination. Since both of these are stimulatory to the 

 germination of this strain (Stewart and Halvorson, 1953), the reactions in- 

 volving heat or adenosine activation of glucose oxidation may be common 

 to those reactions responsible for germination. It is not unlikely that other 

 germinating agents, such as alanine, may also serve as activating agents for 

 dormant enzymes. 



References 



Church, B. D. and H. Halvorson. 1955. Glucose metabolism by resting 

 spores of aerobic bacilli. Bact. Proc. 41. 



Church, B. D. and H. Halvorson. 1956. Effect of heating and aging on ger- 

 mination and glucose oxidation of spores of aerobic bacilli. Bact. Proc. 

 45. 



Murrell, W. G. 1955. The bacterial endospore. Monograph published by the 

 University of Sydney, Australia. 



Murty, G. G. K. and H. Orin Halvorson. 1956. Effect of heat shock and 

 germinating nutrients upon respiration of bacterial spores. Bact. Proc. 

 46. 



Stewart, B. T. and H. Orin Halvorson. 1953. Studies on the spores of aero- 

 bic bacteria. I. The occurrence of alanine racemase. J. Bact. 65: 160-166. 



Swartz, M. N., N. 0. Kaplan, and M. E. Freeh. 1956. Significance of "heat 

 activated" enzymes. Science 123: 50-53. 



Informal Discussion 



Lawrence: I have obtained some data which may bear on the possible 

 relationship of dipicolinic acid to heat resistance, as mentioned by Dr. 

 Murty. 



